Slideshow: Slideshow: High-profile people who left or are leaving Trump administration

Tillerson announced Tuesday he'd turn over his duties to the deputy secretary. (Source: CNN)

President Donald Trump announced Tuesday that Rex Tillerson was out as secretary of state. (Source: CNN)

Former White House aide John McEntee steps off Marine One at the White House, Sunday, March 19, 2017, in Washington. (AP Photo/Alex Brandon)

(RNN) - Secretary of State Rex Tillerson's last day in office will be March 31.

Tillerson announced Tuesday that he would immediately relinquish the duties of his office to Deputy Secretary of State John Sullivan.

"At the end of the day, I'm delegating all responsibilities of the Office of the Secretary to Deputy Secretary of State Sullivan," Tillerson said in a public address after his firing was announced. "My commission as secretary of state will terminate at midnight, March 31."

CNN also reported late Tuesday afternoon that Tillerson's chief of staff Margaret Peterlin and deputy chief of staff Christine Ciccone submitted their resignations, according to State Department officials.

Tillerson said he received a phone call from President Donald Trump Tuesday hours after his firing by the president on Twitter. Trump tweeted that Tillerson would be replaced by current CIA Director Mike Pompeo.

Gina Haspel, the deputy director of the CIA, is Trump's pick to take over for Pompeo. If confirmed, she would be the first female head of the intelligence agency.

"Mike Pompeo, Director of the CIA, will become our new Secretary of State," Trump tweeted. "He will do a fantastic job! Thank you to Rex Tillerson for his service! Gina Haspel will become the new Director of the CIA, and the first woman so chosen. Congratulations to all!"

Mike Pompeo, Director of the CIA, will become our new Secretary of State. He will do a fantastic job! Thank you to Rex Tillerson for his service! Gina Haspel will become the new Director of the CIA, and the first woman so chosen. Congratulations to all!

The New York Times reported in 2017 that Haspel had overseen the torture of suspects and later the destruction of videotapes documenting it while serving in Thailand as a clandestine officer with the agency. A promotion to run clandestine operations had been blocked by Sen. Dianne Feinstein, D-CA, of the Senate Intelligence Committee, due to Haspel's reported role in "enhanced interrogations."

Trump said Tuesday outside the White House that he respected Tillerson and the two got along well, but they disagreed on some issues. He said he made the decision to dismiss the secretary on his own.

Undersecretary for Public Diplomacy Steve Goldstein told CNN that Tillerson had not spoken to Trump and was unaware of the reason he was fired. Goldstein told reporters that Tillerson only learned of his firing from Trump's tweet.

Senate Foreign Relations Chair Bob Corker said in a statement that a hearing on Pompeo's confirmation will be held in April.

"The committee will consider his nomination as expeditiously as possible," he said.

During his public address Tuesday, Tillerson expressed his desire for an orderly transfer of power.

"What is most important is to ensure an orderly and smooth transition during the time that the country continues to face significant policy and national security challenges," Tillerson said.

The outgoing secretary expounded on those security challenges, singling out Russia as a particularly dangerous foreign power.

"Much work remains to respond to the troubling behavior and actions on the part of the Russian government," Tillerson said. "Russia must assess carefully as to how its actions are in the best interest of the Russian people, and of the world more broadly. Continuing on their current trajectory is likely to lead to greater isolation on their part – a situation which is not in anyone's interest."

On Monday, Tillerson joined Great Britain in blaming Russia for the poisoning of an ex-spy living in England. He said he didn't know if the Russian government was directly involved, but the nerve agent clearly came from Russia and "certainly will trigger a response."

Tillerson had cut short his diplomatic trip to Africa, returning to Washington, DC, on Monday. The trip to Africa was among the first high-profile visits by an administration official since Trump had reportedly referred to countries there as "s---hole countries" in January.

The New York Times reported that White House Chief of Staff John Kelly told Tillerson on Friday to come home early, warning him of the firing by saying: "You may get a tweet."

John McEntee, the president's personal assistant, also lost his job and was escorted out of the White House on Monday, reportedly over an issue with his security clearance. An early volunteer on Trump's campaign, the former college football quarterback and Fox News staffer had been one of the longest-serving members of Trump's team and a close confidante of the president, Politico reported.

McEntee is a focus of a Department of Homeland Security investigation into financial crimes, per CNN. Trump's re-election campaign announced McEntee would become a senior adviser for campaign operations.

Tillerson, the former ExxonMobil CEO, navigated storms involving Trump's decision to cease implementing the Paris Climate Accord and questions over Russian meddling in the 2016 election. The secretary and the president issued public statements contradicting each other multiple times on matters of foreign affairs, most recently with the news Thursday that Trump plans to meet with North Korean dictator Kim Jong-un.

Tillerson also had sided with defense chief Jim Mattis in taking a more measured and less aggressive approach toward Kim than the president, according to CNN.

Tillerson follows chief economic adviser Gary Cohn and communications director Hope Hicks as the latest members of the administration to depart. Several other senior members have been fired or resigned in Trump's first 14 months in office, including national security adviser Mike Flynn, head of Health and Human Services Tom Price, chief of staff Reince Priebus and chief strategist Steve Bannon.

Pompeo, confirmed as CIA director in January 2017, had served in the House as the representative from Kansas' 4th District from 2011 to 2017.

"His confirmation may take weeks or even months in advance of the summit of the century," Sen. Richard Blumenthal, D-Conn, told CNN regarding the upcoming planned meeting between Trump and Kim Jong-un. "So this move is very disconcerting and disturbing for American foreign policy."

Tillerson's nomination as head of the State Department passed a Senate panel by a 11-10 party line vote on Jan. 23. He was approved by the full Senate on a 56-43 vote mostly along party lines on Feb. 1. The GOP holds a 52-48 margin in the Senate.

Tillerson came under scrutiny for his past business relationship with Russian President Vladimir Putin. The backers of the oil industry veteran said his ties with the Russian leader were just part of the job for a CEO of a worldwide company.

The Texas graduate in civil engineering worked 41 years at Exxon, rising from an engineer to become CEO in 2006.

Tillerson earned a Distinguished Eagle Scout designation as a youth. He is a former member of the Boy Scouts of America Executive Committee and served as national president of the Boy Scouts from 2010 to 2012.

U.S. President Donald Trump's nominee to head the U.N. migration agency acknowledges a controversy over his social media posts about Muslims and other topics, but insists "retweets are not endorsements" and says he...More >>

U.S. President Donald Trump's nominee to head the U.N. migration agency acknowledges a controversy over his social media posts about Muslims and other topics, but insists "retweets are not endorsements" and says he wants to be judged on his actions.More >>

(AP Photo/Evan Vucci, File). FILE - In this March 15, 2018, file photo, President Donald Trump talks with reporters during a meeting in the Oval Office of the White House in Washington. Trump is questioning the impartiality of Robert Mueller's investig...

The president has long been frustrated by the lengthy and intensifying probe and insists his 2016 presidential campaign did not collude with Russia to influence the election in his favor.

(AP Photo/Elise Amendola, File). FILE - This Monday, June 19, 2017, file photo shows a user signing in to Facebook on an iPad, in North Andover, Mass. Facebook has a problem it just can’t kick: People keep exploiting it in ways that could sway election...

News reports that Facebook let the Trump-affiliated data mining firm Cambridge Analytica abscond with data from tens of millions of users mark the third time in roughly a year the company appears to have been outfoxed in this way.

News reports that Facebook let the Trump-affiliated data mining firm Cambridge Analytica abscond with data from tens of millions of users mark the third time in roughly a year the company appears to have been outfoxed in this way.